1. Field of the Invention
This invention relates to a double barrel dispensing container and a cap for simultaneously closing both outlets of the container.
2. Description of the Related Art
Double barrel dispensing containers such as double barrel syringes are useful for storing different reactive ingredients which, once dispensed, are mixed together to form a desired composition. As an example, a two barrel container may hold an epoxy resin in one chamber and a curing agent in another chamber, so that portions of the resin and curing agent are simultaneously dispensed for immediate mixing and no measuring of the separate ingredients is necessary.
One example of a double barrel dispensing syringe is described in U.S. Pat. No. 4,538,920 which is assigned to the assignee of the present invention. The syringe has two interconnected plungers for simultaneously dispensing proportioned amounts of material from each barrel. An exit conduit is releasably connected to the syringe and has a plurality of helical mixing elements so that the two ingredients are thoroughly mixed once discharged from the exit conduit and mixing by hand may be avoided.
Typically, only a portion of the materials are dispensed at any one time from the barrels of the syringe shown in U.S. Pat. No. 4,538,920, and it is often desirable to cover the side-by-side outlets of the syringe between dispensing operations in order to prevent undue hardening or drying of the liquid materials therein. In the past, certain dispensing syringes have been provided with caps having threads that receive mating threads surrounding the outlets of the syringe. Other types of double barrel syringes are provided with a unitary cap having flexible, protruding closure portions which releasably fit into side-by-side outlets of the syringe.
However, many conventional caps for double barrel dispensing containers may contribute to cross-contamination of the remaining materials within the barrels. If, for instance, small quantities of the materials within the barrels are deposited on closure portions of the cap covering the syringe outlets, these quantities of materials may react with materials in another barrel if the cap is removed for dispensing and then inadvertently replaced in opposite orientation such that each closure portion of the cap covers an outlet which is different from the outlet previously covered. Although the amount of cross-contamination may be relatively small compared to remaining materials within the barrel, such cross-contamination may lead to hardened lumps within the otherwise liquid mixture when dispensed, and may also hinder passage of the materials along the tortuous path presented by the helical static mixing elements.
One known type of dispensing container cap is shaped for push-on installation on a smooth, cylindrical, protruding neck of a double barrel dispensing container. This type of cap has an inner, cylindrical wall with an elongated slot or recess that receives a radially inwardly extending orientating section which is formed on the neck in order to prevent coupling of the cap to the container unless a certain one of two closure portions on the cap is oriented to close a certain one of the two outlets. While such an arrangement may minimize the possibility of cross-contamination of materials remaining with the container, there is a need for a dispensing container and a cap which may be quickly and securely coupled to the container without the possibility of accidental release from the latter. It would also be desirable if the container was constructed to quickly, releasably lock onto conventional threaded exit conduits when desired.